T-slot aluminum extrusions are used for various applications, ranging from test rig, to assembly jig, to machine frame. However, despite their potential, they have achieved limited market traction. In fact, much industrial equipment still relies on welded steel structures, which have long lead-time and are costly to design and manufacture. Suboptimal performance in term of assembly tolerance, admissible load, and structural rigidity represent one of the main technology impediment to a wider adoption of T-slot aluminum extrusions for industrial applications.
Since they were introduced in the industry, aluminum extrusions have used assembly plates combined to T-nuts and bolts to create complete assembled frames. Unfortunately, gain in assembly speed of such concept is done at the expense of assembly tolerances. In at least some of the commercially available extrusion systems, T-slot bolts are acting as the assembly plate locating device and holding device. “Normal or close fit” on assembly plate holes and T-slot groove of the extrusion enables assembly plates to be tighten in off position, thereby propagating angular error throughout the assembled structure. The resulting assembled frame typically has poor perpendicularity and parallelism.
In addition, T-slot aluminum extrusion systems are non-linear systems when subject to heavy load (i.e., as opposed to welded structure assemblies, having a wider range of linear properties). Intermittent slippage of T-nuts inside a T-slot groove when submitted to heavy-load, is one of the primary contributor to non-linearity. Non-linearity of T-slot extrusion system makes it complex to predict structural deformation and failure. Trying to correct T-nuts slippage and non-linearity by simply increasing torque in the T-nuts bolt could leads to other issues such as each side of the T-slot groove separating under plastic deformation. This “pull out” phenomenon makes the damaged extrusion unusable.
Therefore, there is a need for an improved extrusion structure that overcomes at least some of the above-identified limitations of the prior art.